Bone Health and Calcium
1. What is Calcium?
Calcium is the most important mineral in the body, the bones and teeth contain 99% of the calcium in your body. The remaining 1% is presented in blood, extracellular fluid, muscle, and other tissues. Calcium is essential for the heart, muscles and nerves to function properly and for blood to clot, it is also essential for respiration, renal function, vascular contraction, vasodilation, glandular secretion, cell membrane and capillary permeability, enzyme reactions, and neurotransmitter and hormone release and storage (1).
Each day, you lose calcium through your skin, nails, hair, sweat, urine and feces. Your bodies cannot produce calcium. That's why it's very important to get enough calcium from the foods you eat.
When you don't get enough calcium for your body's needs, calcium is automatically taken from your bones. This can make your bones weak and break easily.
2. Poor Bone Health is Common and Costly
According to the US Surgeon General's Report 2004 on Bone Health and Osteoporosis, approximately 34 million Americans have reduced bone mass and ten million have osteoporosis. Half of women and one quarter of men over the age of 50 will have osteoporosis-related fracture sometime during their lifetime. According to US NOF (National Osteoporosis Foundation), by 2020, 61 million Americans will have low bone mass and osteoporosis (2).
1.5 million people are hurt each year in US due to fractures from osteoporosis.
500,000 people are hospitalized each year due to osteoporosis.
800,000 people make trips to the emergency room due to osteoporosis.
2.6 million people make visits to the doctor's office due to osteoporosis.
180,000 people are places in nursing homes due to osteoporosis (2).
3. Weak Bones Hurt Us All
Broken bones are very painful at any age. Each year 1.5 million older people in USA will suffer fractures because their bones have become weak. For older people, weak bones can be deadly.
If you are elderly, a broken hip makes you four times more likely to die within three months. If you survive the injury, it often causes your health to spiral downward. One in four people with hip fracture die within first year, and one in five people with a hip fracture will ends up in a nursing home within a year. Many others become isolated, depressed, or frightened to leave home because they fear they will fall.
The cost of weak bones to Americans, their families, and our country is huge. The medical expense for treating broken bones from osteoporosis is as high as $18 billion each year. The cost of care for these patients and the work that is lost adds billions more (2).
4. Why Common Calcium Supplements Do Not Help?
Many calcium supplement are formulated with a variety of salts including calcium carbonate, calcium citrate, calcium lactate, calcium gluconate, and calcium phosphate. The selection of a calcium supplement should be determined by a number of factors, including absorbability, bioavailability, tolerance, solubility in the intestine, and side effects.
Most forms of supplemental calcium have three disadvantages:
1. Low solubility and or low absorbability.
Most calcium supplements have very low absorbability, such as calcium carbonate (the most common calcium form), it is not water soluble and has very low absorbability; another calcium form such as calcium citrate is water soluble, but it still has very low absorbability. Why? Because most forms of supplemental calcium have something in common: They have to produce calcium ions in order to be absorbed in the small intestine. The PH of the small intestinal fluid is 7.0-7.2. At this PH, most calcium ions will form insoluble hydroxides, a gelatinous type of precipitation. It also can form insoluble complexes with substances commonly presented in food, such as phosphates, oxalates, and phytates. This is why most calcium supplements have low absorbability (5).
"The effective absorption of inorganic minerals is generally less than 10%". (5)
2. Low bioavailability.
Most forms of supplemental calcium have to produce calcium ions in order to be absorbed in the small intestine. The calcium ions are absorbed through ion channel in the small intestine, after calcium ions are absorbed to the blood, these ion form of calcium can be secreted through urine and sweat. That is why most common calcium supplements have low bioavailability.
3. Side effects such as: constipation, bloating, destroys vitamins and blocks other nutrients absorption.
Almost all calcium supplements produce calcium ions in order to be absorbed.
One problem is that the calcium ions will form insoluble precipitation with hydroxides, phosphates, oxalates, and phytates which are commonly presented in food. This not only renders the calcium non-absorbable, but also can cause gastrointestinal side effects such as constipation, bloating, and gas due to the coating of the precipitate on the mucous membrane of the small intestine (6).
The other problem is that the mineral ions are catalysts; it can catalyze oxidative destruction of vitamins, and decrease vitamins and its antioxidant effects (5, 6, 7).
This precipitation will absorb other trace nutrients such as trace minerals and vitamins in the small intestine and cause them also to be non-absorbable (5, 6, 7).
5. The Best Calcium Supplement
The most common calcium supplements have three disadvantages: low absorbability, low bioavailability, and side effects. All these disadvantages are caused by the calcium ions in the small intestine, and the common calcium forms have to produce calcium ions on order to be absorbed. To eliminate these problems, Noble Prize winner Alfred Werner mentioned chelated mineral theory many years ago. If mineral ions are chelated with amino acids, they will have 1. High absorbability. 2. High bioavailability. 3. No side effects such as constipation, destroy vitamins and block vitamins and nutrients absorption.
The calcium in MaxCal+ is in the most advanced amino acid chelated form. This amino acid chelated calcium has three advantages:
1. 100% soluble and highest absorbability.
The chelated minerals are especially surrounded and well-shielded by several unique amino acids, the bonds between mineral ions and amino acids are so strong that it will resist any anion attack even at PH 11. Chelated mineral ions can not come out to form precipitate in the small intestine; that is why MaxCal+ minerals always keep soluble and readily absorbable in the small intestine (5, 6, 8, 9, 10, 11, 12, 13).
2. Highest bioavailability.
Calcium in MaxCal+ is actively absorbed in the body by passing through special amino acid channel in the small intestine. This absorption is very fast and effective, and after MaxCal+ is absorbed to the blood, the calcium in MaxCal+ is still be chelated with amino acids and it will not be secreted to the urine and sweat. That is why MaxCal+ has highest bioavailability (9, 10).
3. No side effects such as: constipation, bloating, destruction of vitamins and blocking of nutrient absorption.
The minerals in MaxCal+ are in a special amino acid chelated form. These chelated mineral ions can not come out to form precipitate in the small intestine. They will not block other trace minerals and vitamins from absorption, and will not cause constipation, bloating, gas or other side effects (5, 6, 8).
Because this chelated mineral ions can not come out to catalyze oxidative destruction of vitamins. MaxCal+ will preserve vitamin's stability and antioxidant effects (5, 6).
6. Comparison of Different Calcium Forms
7. Tips for maintaining strong bones:
8. Scientific Reports about Calcium
Build Healthy Bones. Taking calcium orally is effective for preventing and treating bone loss and osteoporosis. Multiple clinical studies and meta-analyses suggest efficacy for calcium plus vitamin D for primary prevention of osteoporosis ((14, 15,16,17,18, 19, 20, 21, 22) *.
Bone loss is more pronounced if dietary calcium intake is below the RDA, which is the case for many. (23, 24) *.
Bone loss in premenopausal women over age 40 can be reduced significantly by supplementing with 1000 mg calcium/day (24) *.
The typical rate of bone loss in postmenopausal women who are not taking calcium supplements is 2% per year (25, 26).
Calcium 1000-1600 mg/day decreases this rate by 0.25% to 1% annually (27, 28, 29, 30, 23, 25, 31, 26, 24, 32) *.
30 years of continuous calcium supplementation after menopause might result in a 50% overall reduction in fracture rates, compared with women who do not take calcium supplements. (33) *.
Most studies show that long-term calcium supplementation decreases primary fracture rates for specific bones by 30% to 35% for vertebral bone and 25% for hip bone (26) *.
Reduce Diabetes. Some population research suggests that a higher intake of calcium from diet and supplements alone or in combination with vitamin D is associated with a lower risk of developing type 2 diabetes compared to lower calcium intake (34, 35) *.
Reduce Hypertension. Several clinical trials show that taking calcium supplements modestly reduces blood pressure. Calcium seems to be more effective for certain subpopulations of patients, such as salt-sensitive people and patients with low baseline dietary calcium intake (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47) *.
Population research also suggests that women aged 45 years and older, with higher intake of calcium, seem to have a lower risk of developing hypertension compared to women with lower calcium intake (34) *.
Some clinical research shows that taking calcium orally reduces blood pressure in patients with end-stage renal disease (ESRD) (48) *.
Reduce Breast Cancer. Population research shows that higher intake of calcium is associated with a significantly reduced risk of developing breast cancer in premenopausal women (49) *.
Weight Loss. Adults and children with low calcium intake are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese compared to people with high calcium intake. (50, 51, 52, 53, 54, 55) *.
According to some analyses of calcium studies, an increase in dietary calcium consumption of 900-1000 mg/day is associated with an 8-9 kilogram reduction in body weight in adults (50, 54) *.
Lower Cholesterol. Taking calcium supplements in conjunction with a low-fat or calorie-restricted diet might modestly reduce cholesterol (56) *.
Reduce any Type of Cancer. A clinical trial shows that healthy postmenopausal women who take supplemental calcium 1400-1500 mg/day plus vitamin D3 (cholecalciferol) 1100 IU/day have a 60% lower relative risk for developing cancer of any type (57) *.
Reduce Premenstrual Syndrome (PMS). There seems to be a link between low dietary calcium intake and symptoms of PMS. (58).
Taking calcium 1-1.2 grams daily seems to significantly reduce depressed mood, water retention, and pain associated with PMS (59, 60, 61) *.
Reduce Ischemic Stroke. There is some evidence that increasing dietary calcium intake might decrease the relative risk of ischemic stroke in women. (62) *.
Reduce Prostate Cancer. Some research suggests that taking a calcium supplement 1200 mg/day might decrease the risk of developing prostate cancer. (63) *.
Build Healthy Fetal Bone. Calcium supplementation, in pregnant women who have low dietary calcium intake, increases fetal bone mineralization and density. (64, 65) *.
Reduce Corticosteroid-induced Osteoporosis. Taking calcium in combination with vitamin D as adjunctive therapy seems to be effective for reducing bone mineral density loss in people using corticosteroids long-term. (66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77) *.
Reduce Colorectal Cancer. Population studies suggest that high intake of dietary or supplemental calcium seems to reduce the risk of colorectal cancer. (78, 79, 80) *.
Clinical trials also show that taking calcium supplements can reduce the risk of colorectal adenoma recurrence. (81, 82, 83, 84) *.
Help Tooth Retention. Taking calcium and vitamin D orally appear to beneficially affect tooth retention in the elderly population. (85).
Reduce Cramps. There is preliminary clinical evidence that taking calcium 1 gram twice daily can reduce pregnancy-related leg cramps during the second half of pregnancy. (86).
9. How Much Calcium Do You Need Per Day?
- 1. McKevoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
- 2. The 2004 Surgeon General's Report on Bone Health and Osteoporosis
- 3. Committee on School Health soft drinks in schools. Pediatrics 2004; 113(1Pt 1):152-154
- 4. The National Health and Nutrition Examination Survey (NHANES) data on dietary intake of selected minerals 1999-2000.
- 5. Fouad, M.T. “Chelation and chelated minerals” J. Appl. Nutr. 28:6
- 6. Fang S.M., S.A. Burton and R.V. Peterson, “Bioavailability of zinc: effect of amino acid chelation.” Chelated Mineral Nutrition implants, Animal and Man Charles C. Thomas Publisher, Springfield, IL pp.134-151.
- 7. F.M. Clydesdale, Ph.D. “The relevance of mineral chemistry to bioavalability” NUTRITION TODAY March/April 1989
- 8. Greger JL and Krashoc Cl. “Effects of a variety of calcium source on mineral metabolism in anemic rats.” Drug Nutr Interact 1988,5(4) 387-94
- 9. Kratzer F et al. Chelates in Nutrition. CRC Press, Florida, 1986
- 10. Ashmead, HD et al. Intestinal absorption of Metal Ions and Chelates, Charles C. Thomas Publisher, Springfield III. 1985.
- 11. Kaemmerer, V.K. et al. “studies with organic and inorganic copper compounds. 1. Oral substitutions of a copper deficiency situation in rats and pigs. Zbl. Vet. Med. 31:645
- 12. Scholmerich, J.A. et al. “Bioavailability of zinc from zinc-histidine complexes. 1. Comparison with zinc sulfate in healthy men” Am. J. Clin. Nutr. 45:1480 1987
- 13. Snedeker, S.M. et al. “Metabolism of zinc, copper and iron as affected by dietary protein, cysteine and histidine.” J. Nutr. 113:644 1983
- 14. Dawson-Hughes B, Harris SS, Krall EA, Dallal GE. Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older. N Engl J Med 1997;337:670-6.
- 15. Chapuy MC, Arlot ME, Duboeuf F, et al. Vitamin D3 and calcium to prevent hip fractures in the elderly women. N Engl J Med 1992;327:1637-42.
- 16. Chapuy MC, Pamphile R, Paris E, et al. Combined calcium and vitamin D3 supplementation in elderly women: confirmation of reversal of secondary hyperparathyroidism and hip fracture risk: the Decalyos II study. Osteoporos Int 2002;13:257-64.
- 17. NIH Consensus Development Panel on Osteoporosis Prevention, Diagnosis, and Therapy. Osteoporosis prevention, diagnosis, and therapy. JAMA 2001;285:785-95.
- 18. National Osteoporosis Foundation. Physician's Guide to Prevention and Treatment of Osteoporosis. Universal Recommendations for All Patients. Available at: http://www.nof.org/physguide/univeral_recommendations.htm#adequate. (Accessed 14 May 2005).
- 19. Larsen ER, Mosekilde L, Foldspang A. Vitamin D and calcium supplementation prevents osteoporotic fractures in elderly community dwelling residents: a pragmatic population-based 3-year intervention study. J Bone Miner Res 2004;19:370-8.
- 20. Bischoff-Ferrari HA, Willett WC, Wong JB, et al. Fracture prevention with vitamin D supplementation: a meta-analysis of randomized controlled trials. JAMA 2005;293:2257-64.
- 21. Boonen S, Body JJ, Boutsen Y, et al. Evidence-based guidelines for the treatment of postmenopausal osteoporosis: a consensus document of the Belgian Bone Club. Osteoporos Int 2005;16:239-54.
- 22. Papadimitropoulos E, Wells G, Shea B, et al. Meta-analyses of therapies for postmenopausal osteoporosis. VIII: Meta-analysis of the efficacy of vitamin D treatment in preventing osteoporosis in postmenopausal women. Endocr Rev 2002;23:560-9.
- 23. McGarry KA, Kiel DP. Postmenopausal osteoporosis. Strategies for preventing bone loss, avoiding fracture. Postgrad Med 2000;108:79-82,85-88, 91.
- 24. Bryant RJ, Cadogan J, Weaver CM. The new dietary reference intakes for calcium: implications for osteoporosis. J Am Coll Nutr 1999;18:406S-412S.
- 25. Nieves JW, Komar L, Cosman F, Lindsay R. Calcium potentiates the effect of estrogen and calcitonin on bone mass: review and analysis. Am J Clin Nutr 1998;67:18-24.
- 26. Kanis JA. The use of calcium in the management of osteoporosis. Bone 1999;24:279-90.
- 27. Storm D, Eslin R, Porter ES, et al. Calcium supplementation prevents seasonal bone loss and changes in biochemical markers of bone turnover in elderly New England women: a randomized, placebo-controlled trial. J Clin Endocrinol Metab 1998;83:3817-25.
- 28. Riggs BL, O”Fallon WM, Muhs J, et al. Long-term effects of calcium supplementation on serum parathyroid hormone level, bone turnover, and bone loss in elderly women. J Bone Miner Res 1998;13:168-74.
- 29. Devine A, Dick IM, Heal SJ, et al. A 4-year follow-up study of the effects of calcium supplementation on bone density in elderly postmenopausal women. Osteoporos Int 1997;7:23-8.
- 30. Heaney RP. Calcium, dairy products and osteoporosis. J Am Coll Nutr 2000;19:83S-99S.
- 31. Deal C. Can calcium and vitamin D supplementation adequately treat most patients with osteoporosis? Cleve Clin J Med 2000;67:696-8.
- 32. Castelo-Branco C, Pons F, Vicente JJ, et al. Preventing postmenopausal bone loss with ossein-hydroxyapatite compounds. Results of a two-year, prospective trial. J Reprod Med 1999;44:601-5.
- 33. Chiu KM. Efficacy of calcium supplements on bone mass in postmenopausal women. J Gerontol A Biol Sci Med Sci 1999;54:M275-80. 33. Heaney RP, Rafferty K. Carbonated beverages and urinary calcium excretion. Am J Clin Nutr 2001;74:343-7. 31. Deal C. Can calcium and vitamin D supplementation adequately treat most patients with osteoporosis? Cleve Clin J Med 2000;67:696-8.
- 34. Liu S, Song Y, Ford ES, et al. Dietary calcium, vitamin D, and the prevalence of metabolic syndrome in middle-aged and older US women. Diabetes Care 2005;28:2926-32.
- 35. Pittas AG, Lau J, Hu FB, Dawson-Hughes B. The role of vitamin d and calcium in type 2 diabetes. A systematic review and meta-analysis. J Clin Endocrinol Metab 2007;92:2017-29.
- 36. Shils M, Olson A, Shike M. Modern Nutrition in Health and Disease. 8th ed. Philadelphia, PA: Lea and Febiger, 1994.
- 37. Whelton PK, Kumanyika SK, Cook NR, et al. Efficacy of nonpharmacologic interventions in adults with high-normal blood pressure: results from phase 1 of the trials of hypertension prevention (TOHP). Trials of Hypertension Prev (TOHP) Collab Res Group. Am J Clin Nutr 1997;65:652S-60S.
- 38. Yamamoto ME, Applegate WB. Klag MJ, et al. Lack of blood pressure effect with calcium and magnesium supplementation in adults with high-normal blood pressure. Results from phase I of the trials of hypertension prevention (TOHP). Trials of Hypertension Prev (TOHP) Collab Res Group. Ann Epidemiol 1995;5:96-107.
- 39. Weinberger MH, Wagner UL, Fineberg NS. The blood pressure effects of calcium supplementation in humans of known sodium responsiveness. Am J Hypertens 1993;6:799-805.
- 40. Dwyer JH, Dwyer KM, Scribner RA, et al. Dietary calcium, calcium supplementation, and blood pressure in African American adolescents. Am J Clin Nutr 1998;68:648-55.
- 41. Allender PS, Cutler JA, Follmann D, et al. Dietary calcium and blood pressure: a meta-analysis of randomized clinical trials. Ann Intern Med 1996;124:825-31.
- 42. Bucher HC, Cook RJ, Guyatt GH, et al. Effects of dietary calcium supplementation on blood pressure. A meta-analysis of randomized controlled trials. JAMA 1996;275:1016-22.
- 43. Kawano Y, Yoshimi H, Matsuoka H, et al. Calcium supplementation in patients with essential hypertension: assessment by office, home and ambulatory blood pressure. J Hypertens 1998;16:1693-9.
- 44. Griffith LE, Guyatt GH, Cook RJ, et al. The influence of dietary and nondietary calcium supplementation on blood pressure: an updated meta-analysis of randomized controlled trials. Am J Hypertens 1999;12:84-92.
- 45. Jorde R, Bonaa KH. Calcium from dairy products, vitamin D intake, and blood pressure: the Tromso study. Am J Clin Nutr 2000;71:1530-5.http://books.nap.edu/books/0309063507/html/index.html.
- 46. Reid IR, Horne A, Mason B, Ames R, Bava U, Gamble GD. Effects of calcium supplementation on body weight and blood pressure in normal older women: A Randomized Controlled Trial. J Clin Endocrinol Metab 2005;90:3824-9.
- 47. van Mierlo LA, Arends LR, Streppel MT, et al. Blood pressure response to calcium supplementation: a meta-analysis of randomized controlled trials. J Hum Hypertens 2006;20:571-80.
- 48. Petersen LJ, Rudnicki M, Hojsted J. Long-term oral calcium supplementation reduces diastolic blood pressure in end stage renal disease. A randomized, double-blind, placebo-controlled study. Int J Artif Organs 1994;17:37-40.
- 49. Lin J, Manson JE, Lee IM, et al. Intakes of calcium and vitamin D and breast cancer risk in women. Arch Intern Med 2007;167:1050-9.
- 50. Heaney RP, Davies KM, Barger-Lux MJ. Calcium and weight: clinical studies. J Am Coll Nutr 2002;21:152S-5S.
- 51. Buchowski MS, Semenya J, Johnson AO. Dietary calcium intake in lactose maldigesting intolerant and tolerant African-American women. J Am Coll Nutr 2002;21:47-54.
- 52. Tanasescu M, Ferris AM, Himmelgreen DA, et al. Biobehavioral factors are associated with obesity in Puerto Rican children. J Nutr 2000;130:1734–42.
- 53. Jacqmain M, Doucet E, Després JP, et al. Calcium intake, body composition, and lipoprotein-lipid concentrations in adults. Am J Clin Nutr 2003;77:1448–52.
- 54. Davies KM, Heaney RP, Recker RR, et al. Calcium intake and body weight. J Clin Endocrinol Metab 2000;85:4635-8.
- 55. Lorenzen JK, Molgaard C, Michaelsen KF, Astrup A. Calcium supplementation for 1 y does not reduce body weight or fat mass in young girls. Am J Clin Nutr 2006;83:18-23.
- 56. Bell L, Halstenson CE, Halstenson CJ, et al. Cholesterol-lowering effects of calcium carbonate in patients with mild to moderate hypercholesterolemia. Arch Intern Med 1992;152:2441-4.
- 57. Lappe JM, Travers-Gustafson D, Davies KM, et al. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr 2007;85:1586-91.
- 58. Bendich A. The potential for dietary supplements to reduce premenstrual syndrome (PMS) symptoms. J Am Coll Nutrition 2000;19:3-12.
- 59. Thys-Jacobs S, Starkey P, Bernstein D, Tian J. Calcium carbonate and the premenstrual syndrome: effects on premenstrual and menstrual symptoms. Premenstrual Syndrome Study Group. Am J Obstet Gynecol 1998;179:444-52.
- 60. Alvir JM, Thys-Jacobs S. Premenstrual and menstrual symptom clusters and response to calcium treatment. Psychopharmacol Bull 1991;27:145-8.
- 61. Thys-Jacobs S, Ceccarelli S, Bierman A, et al. Calcium supplementation in premenstrual syndrome: a randomized crossover trial. J Gen Intern Med 1989;4:183-9.
- 62. Iso H, Stampfer MJ, Manson JE, et al. Prospective study of calcium, potassium, and magnesium intake and risk of stroke in women. Stroke 1999;30:1772-9.
- 63. Baron JA, Beach M, Wallace K, et al. Risk of prostate cancer in a randomized clinical trial of calcium supplementation. Cancer Epidemiol Biomarkers Prev 2005;14:586-9.
- 64. Koo WK, Walters JC, Esterlitz J, et al. Maternal calcium supplementation and fetal bone mineralization. Obstet Gynecol 1999;94:577-82.
- 65. Raman L, Rajalakshmi K, Krishnamachari KAVR, et al. Effect of calcium supplementation to undernourished mothers during pregnancy on the bone density of the neonates. Am J Clin Nutr 1978; 31:466-9.
- 66. Bernstein CN, Seeger LL, Anton PA, et al. A randomized, placebo-controlled trial of calcium supplementation for decreased bone density in corticosteroid-using patients with inflammatory bowel disease: a pilot study. Aliment Pharmacol Ther 1996;10:777-86.
- 67. Buckley LM, Leib ES, Cartularo KS, et al. Calcium and vitamin D3 supplementation prevents bone loss in the spine secondary to low-dose corticosteroids in patients with rheumatoid arthritis. A randomized double-blind, placebo-controlled trial. Ann Intern Med 1996;125:961-8.
- 68. Adachi JD, Ioannidis G. Calcium and vitamin D therapy in corticosteroid-induced bone loss: what is the evidence? Calcif Tissue Int 1999;65:332-6.
- 69. Adachi JD, Bensen WG, Bianchi F, et al. Vitamin D and calcium in the prevention of corticosteroid induced osteoporosis: a 3 year followup. J Rheumatol 1996;23:995-1000.
- 70. Recommendations for the prevention and treatment of glucocorticoid-induced osteoporosis. American College of Rheumatology Task Force on Osteoporosis Guidelines. Arthritis Rheum 1996;39:1791-801.
- 71. Lems WF, Van Veen GJ, Gerrits MI, et al. Effect of low-dose prednisolone (with calcium and calcitriol supplementation) on calcium and bone metabolism in healthy volunteers. Br J Rheumatol 1998;37:27-33.
- 72. Reid DM, Kennedy NS, Smith MA, et al. Total body calcium in rheumatoid arthritis: Effects of disease activity and corticosteroid treatment. Br Med J (Clin Res Ed) 1982;285:330-2.
- 73. Lems WF, Jacobs JW, Netelenbos JC, et al. [Pharmacological prevention of osteoporosis in patients on corticosteroid medication]. [Article in Dutch]. Ned Tijdschr Geneeskd 1998;142:1904-8.
- 74. Gennari C. Differential effect of glucocorticoids on calcium absorption and bone mass. Br J Rheumatol 1993;32:11-4.
- 75. Need AG, Philcox JC, Hartley TF, et al. Calcium metabolism and osteoporosis in corticosteroid-treated postmenopausal women. Aust N Z J Med 1986;16:341-6.
- 76. Reid IR, Ibbertson HK. Calcium supplements in the prevention of steroid-induced osteoporosis. Am J Clin Nutr 1986;44:287-90.
- 77. Homik J, Suarez-Almazor ME, Shea B, et al. Calcium and vitamin D for corticosteroid-induced osteoporosis. Cochrane Database Syst Rev 2000;(2):CD000952.
- 78. White E, Shannon JS, Patterson RE. Relationship between vitamin and calcium supplement use and colon cancer. Cancer Epidemiol Biomarkers Prev 1997;6:769-74.
- 79. Terry P, Baron JA, Bergkvist L, et al. Dietary calcium and vitamin D intake and risk of colorectal cancer: a prospective cohort study in women. Nutr Cancer 2002;43:39-46.
- 80. Cho E, Smith-Warner SA, Spiegelman D, et al. Dairy foods, calcium, and colorectal cancer: a pooled analysis of 10 cohort studies. J Natl Cancer Inst 2004;96:1015-22.
- 81. Baron JA, Beach M, Mandel JS, et al. Calcium supplements for the prevention of colorectal adenomas. Calcium Polyp Prev Study Group. N Engl J Med 1999;340:101-7.
- 82. Grau MV, Baron JA, Sandler RS, et al. Vitamin D, calcium supplementation, and colorectal adenomas: results of a randomized trial. J Natl Cancer Inst 2003;95:1765-71.
- 83. Weingarten MA, Zalmanovici A, Yaphe J. Dietary calcium supplementation for preventing colorectal cancer and adenomatous polyps. Cochrane Database Syst Rev 2004;(1):CD003548.
- 84. Grau MV, Baron JA, Sandler RS, et al. Prolonged effect of calcium supplementation on risk of colorectal adenomas in a randomized trial. J Natl Cancer Inst 2007;99:129-36.
- 85. Krall EA, Wehler C, Garcia RI, et al. Calcium and vitamin D supplements reduce tooth loss in the elderly. Am J Med 2001;111:452-6.
- 86. Hammar M, Larsson L, Tegler L. Calcium treatment of leg cramps in pregnancy. Effect on clinical symptoms and total serum and ionized serum calcium concentrations. Acta Obstet Gynecol Scand 1981;60:345-7.